Modulation of the caveolin-3 localization to caveolae and STAT3 to mitochondria by catecholamine-induced cardiac hypertrophy in H9c2 cardiomyoblasts

We investigated the effect of phenylephrine (PE)- and isoproterenol (ISO)-induced cardiac hypertrophy on subcellular localization and expression of caveolin-3 and STAT3 in H9c2 cardiomyoblast cells. Caveolin-3 localization to plasma membrane was attenuated and localization of caveolin-3 to caveolae in the plasma membrane was 24.3% reduced by the catecholamine-induced hypertrophy. STAT3 and phospho-STAT3 were up-regulated but verapamil and cyclosporin A synergistically decreased the STAT3 and phospho-STAT3 levels in PE- and ISO-induced hypertrophic cells. Both expression and activation of STAT3 were increased in the nucleus by the hypertrophy. Immunofluorescence analysis revealed that the catecholamine-induced hypertrophy promoted nuclear localization of pY705-STAT3. Of interest, phosphorylation of pS727-STAT3 in mitochondria was significantly reduced by catecholamine-induced hypertrophy. In addition, mitochondrial complexes II and III were greatly down-regulated in the hypertrophic cells. Our data suggest that the alterations in nuclear and mitochondrial activation of STAT3 and caveolae localization of caveolin-3 are related to the development of the catecholamine-induced cardiac hypertrophy.

Changes in Muscular Lipids in Unilateral Isolated Hypertrophy of Gastrocnemius Muscle Can Be Revealed by 1H MR Spectroscopy

OBJECTIVE: To test whether proton magnetic resonance spectroscopy (1H-MRS) reveals changes in the lipid content of the gastrocnemius muscle (GM) and soleus muscle (SOL) of a patient with unilateral isolated hypertrophy of the right GM. MATERIALS AND METHODS: 1H-MRS was performed on a 1.5 Tesla (T) whole-body unit. Muscular lipids inside SOL and GM were assessed in both calves of the patient by a STEAM (stimulated echo acquisition mode) localization sequence. Results were compared to a control group of four healthy volunteers. RESULTS: Total amount of muscular lipids in the hypertrophic GM of the patient was clearly increased compared to the controls (38.7 versus 21.8+/-3.5 a.u.) while intramyocellular lipids of the adjacent SOL were lower compared to the contralateral healthy leg. CONCLUSION: Muscular lipids are substrates for metabolism and can be assessed non-invasively by 1H-MRS. 1H-MRS is considered to be a helpful tool in clinical assessment of muscle metabolism in cases with muscular hypo- or hypertrophy.

Menor expresión de la enzima convertidora de angiotensinaI omóloga (ECA2) se asocia a mayor remodelamiento de la pared aórtica de ratas con niveles geneticamente elevados de angiotensina II / Decreased expression of homologous angiotensin I converting enzyme (ACE2) is associated to increased remodeling of the aortic arterial wall in rats with genetically elevated levels of angiotensin II

Introducción: El polimorfismo de la enzima convertidora de angiotensina I (ECA) determina mayor actividadde ECA y niveles de angiotensina (Ang) II en ratas Brown Norway (BN) y menor actividad de ECA y niveles de Ang II en ratas Lewis (L). La interregulación entre ECA, ECA2 y su relación con remodelamiento aórtico hipertensivo no ha sido explorada Objetivo: Determinar la expresión de ECA y ECA2 y los parámetros de remodelamiento vascular hipertensivo en la aorta de ratas con niveles genéticamente determinados de ECA. Métodos: A ratas macho homocigotas de 150 grs BN y LL, se les indujo HTA por 6 semanas por el procedimiento Goldblatt (GB, 2 K-1clip). Ratas pseudo-operadas se usaron como controles (sham). Se determinó la presión arterial sistólica (PAS), el grosor de la túnica media (GTM), área de la TM (ATM), expresión génica deECA, ECA2 ,TGF-beta, PAI-1 y MCP-1 por RT-PCR y también proteica de ECA y ECA2 por Western Blot. Resultados: La masa cardiaca relativa y la PAS aumentaron significativamente en los grupos GB respecto a sus controles Sham, sin diferencias por efecto del polimorfismo de la ECA. En condiciones de normotensión las ratas BN mostraron que la pared aórtica expresa mayores niveles génicos y proteicos de la ECA(60% y 134%, respectivamente) y menores de ECA2 (74% y 73%, respectivamente) respecto de las ratas L(p<0.05). Estos resultados se asociaron con mayores GTM y ATM como en los niveles de mRNA de TGF-beta y, PAI-1 en las aortas de ratas BN respecto de las ratas L (p<0,05). En respuesta a un estrés hipertensivo las ratas con mayores niveles de ECA y menores niveles de ECA2 mostraron mayor GTM (p<0,05, respecto de GB-L), sin diferencias en los otros parámetros evaluados...

Background: Angiotensin I converting enzyme (ACE) polymorphism determines increased ACE and Ang IIlevels in Brown Norway rats (BN) and decreased ACE and Ang II levels in Lewis (L) rats. The interactionbetween ACE and ACE2 in relation to aortic remodeling associated to hypertension has not been explored. Aim: to determine the expression of ACE and ACE2 along with parameters of remodeling in hypertensive rats with genetically determined levels of ACE. Methods: BN and L rats weighing 150 g were made hypertensive by the Goldblatt procedure (GB, 2K-1 clip). Sham operated rats were used as controls. Systolic blood pressure (SBP), media thickness (MT), and MT area were measured. RT-PCR was used to determine the genetic expression of ACE, ACE2, TGF-beta, PAI-1 and MCP-1. Western Blot was used to measure the protein fraction of ACE and ACE2 Results: Relative cardiac mass and SBP increases significantly in GB rats compared to controls; ACE polymorphism did not influence this effect. The aortic wall of normotensive BN rats expressed increased genic and protein levels of ACE (60% and 134%, respectively) and decreased levels of ACE2 (74% and 73%, respectively) compared to L rats (p<0.05). These findings were associated to increased MT and MT area as well as increased mRNA for TGF-beta and PAI 1 in BN rats compared to L rats (p<0.05). In response to hypertensive stress, rats with increased ACE and decreased ACE2 levels developed increased MT compared to GB-L rats; other parameters of remodeling were not affected...

Proteoglycans production by aortic vascular smooth muscle cells from hypertensive rats

Remodeling of large and small arteries contributes to the development and complications of hypertension. Artery structural changes in chronic sustained hypertension include vascular smooth muscle cells (VSMC) proliferation and extracellular matrix (ECM) modifications. Extracellular constituents such as proteoglycans (PGs), may modulate vascular stiffness and VSMC growth and differentiation. We examined the effect of growth factors on secreted and membrane-bound PGs synthesis by cultured aortic smooth muscle cells (SMC) from 12- to 14- week-old spontaneously hypertensive rats (SHR) and age-matched Wistar rats. After stimulation with platelet-derived growth factor (PDGF-BB), 10% fetal calf serum (FCS) or 0.1% FCS as control, PGs synthesis (dpm/ng DNA) was evaluated in the medium (M-ECM) and in the cell layer (P-ECM) by a double-isotopic label method using both [3H]-glucosamine and [35S]-sodium sulfate which are incorporated into all complex carbohydrates or only into sulfated dysaccharides, respectively. Data are presented as percent of the control (0.1% FCS). SHR VSMC displayed a significantly greater synthesis of M-ECM [3H]-PGs than Wistar rat cells, with both treatments, but no differences in M-ECM [35S] uptake were found in any case. In the P-ECM, both PDGF-BB and 10% FCS produced a greater effect on [3H]-PGs and sulfated PGs synthesis in VSMC from SHR. An important change seen in SHR cells was a significant decreased sulfation, assessed by [35S]/[3H] ratio, in basal and stimulation conditions. Present results indicate the existence of changes in PGS synthesis and modulation in VSMC from a conduit-artery of SHR and support the pathophysiological role proposed for matrix proteoglycans in the vascular wall changes associated to hypertension and related vascular diseases as atherosclerosis.